<template>
    <div class="app-container">
        <h2 style="text-align: center;">发布新课程</h2>

        <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
            <el-step title="填写课程基本信息"/>
            <el-step title="创建课程大纲"/>
            <el-step title="提交审核"/>
        </el-steps>

        <el-form label-width="120px">
            <el-form-item label="课程标题">
                <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频"/>
            </el-form-item>

            <!-- 所属分类 TODO -->
            <el-form-item label="课程分类">

                <el-select v-model="courseInfo.subjectParentId" placeholder="一级分类" @change="subjectLevelOneChanged">
                    <el-option v-for="subject in subjectOneList" :key="subject.id" :label="subject.title" :value="subject.id"/>
                </el-select>

                <!-- 二级分类 -->
                <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
                <el-option v-for="subject in subjectTwoList" :key="subject.id" :label="subject.title" :value="subject.id"/>
                </el-select>
            </el-form-item>
            <!-- 课程讲师 TODO 所属分类：级联下拉列表 一级分类 -->
            <el-form-item label="课程讲师">
                <el-select v-model="courseInfo.teacherId" placeholder="请选择">
                    <el-option v-for="teacher in teacherList" :key="teacher.id" :label="teacher.name" :value="teacher.id"/>
                </el-select>
            </el-form-item>
            <!-- <el-form-item label="课程类别">
                <el-select v-model="courseInfo.subjectParentId" placeholder="请选择">
                    <el-option v-for="subject in subjectNestedList" :key="subject.id"
                    :label="subject.title" :value="subject.id"/>
                </el-select>
            </el-form-item> -->

            <el-form-item label="总课时">
                <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
            </el-form-item>

            <!-- 课程简介 TODO -->
            <!-- 课程简介-->
            <el-form-item label="课程简介">
                <tinymce :height="300" v-model="courseInfo.description"/>
            </el-form-item>

            <!-- 课程封面 TODO -->
            <el-form-item label="课程封面">
                <el-upload
                    :show-file-list="false"
                    :auto-upload="true"
                    :on-success="handleAvatarSuccess"
                    :before-upload="beforeAvatarUpload"
                    :action="BASE_API+'/eduoss/fileoss'"
                    class="avatar-uploader">
                    <img :src="courseInfo.cover">
                </el-upload>
            </el-form-item>
            <el-form-item label="课程价格">
                <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/>
            </el-form-item>
            <el-form-item>
                <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
            </el-form-item>
        </el-form>

    </div>
</template>
<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce'//引入组件

export default{
    //声明组件
    components:{Tinymce},
    data() {
        return {
            saveBtnDisabled:false,
            courseInfo:{
                title: '',
                subjectId: '',//二级分类ID
                subjectParentId:'',//一级分类ID
                teacherId: '',
                lessonNum: 0,
                description: '',
                cover: '/static/love.jpg',
                price: 0
            },
            BASE_API: process.env.BASE_API,
            teacherList:[],//讲师数据
            subjectOneList:[],//一级分类
            subjectTwoList:[],//二级分类
            courseId:''
        }
    },
    created() {
        
        //初始化所有讲师
        this.getListTeacher()
        //初始化一级分类
        this.getOneSubject()
        //获取路由的id
        if (this.$route.params && this.$route.params.id) {
            this.courseId = this.$route.params.id
            this.getInfo();
        } else {
            //初始化所有的讲师
            this.getListTeacher()
            //初始化一级分类
            this.getOneSubject()
        }
    },
    methods:{
        //根据课程ID查询信息
        getInfo() {
            course.getCourseInfoId(this.courseId)
                .then(response => {
                    //在CourseInfo中有基本信息，包括一级分类二级分类
                    this.courseInfo = response.data.courseInfoVo
                    //1查询出所有的分类
                    subject.getSubjectList()
                        .then(response => {
                            //获取所有的一级分类
                            this.subjectOneList = response.data.list
                            
                            //3.把所有的一级分类的数组进行遍历,比较当前courseInfo里面的一级分类id和所有的一级分类id
                            for(var i = 0; i < this.subjectOneList.length; ++i) {
                                //获取每个一级分类
                                var oneSubject = this.subjectOneList[i]
                                //比较一下id
                                if(this.courseInfo.subjectParentId == oneSubject.id) {
                                    //获取一级分类里面所有的二级分类
                                    this.subjectTwoList = oneSubject.children
                                }
                            }
                        })
                })
        },
        //上传封面成功调用的方法
        handleAvatarSuccess(res, file) {
            this.courseInfo.cover = res.data.url
        },//上传之前调用的方法
        beforeAvatarUpload(file) {
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2
            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }
            return isJPG && isLt2M
        },
        //点击一级分类，会触发change事件，显示对应的二级分类
        subjectLevelOneChanged(value) {
            //value就是一级分类id值
            for(var i = 0; i < this.subjectOneList.length; ++i) {
                var oneSubject = this.subjectOneList[i];
                if(oneSubject.id === value) {
                    this.subjectTwoList = oneSubject.children
                    this.courseInfo.subjectId =""
                    break;
                }
            }
        },
        //查询所有的一级分类
        getOneSubject() {
            subject.getSubjectList()
                .then(response => {
                    this.subjectOneList = response.data.list;
                })
        },
        //查询所有的讲师
        getListTeacher() {
            course.getListTeacher()
                .then(response => {
                    this.teacherList = response.data.items
                })
        },
        //添加课程
        addCourse() {
            course.addCourseInfo(this.courseInfo)
                .then(response => {
                    this.$message({
                        type:'success',
                        message:'添加课程信息成功'
                    })
                    //跳转到下一个
                    this.$router.push({path:'/course/chapter/' + response.data.courseId})
                })
        },
        //修改课程
        updateCourse() {
            course.updateCourseInfoId(this.courseInfo)
                .then(response => {
                    this.$message({
                        type:'success',
                        message:'修改课程信息成功'
                    })
                    //跳转到下一个
                    this.$router.push({path:'/course/chapter/' + this.courseId})
                })
        },
        saveOrUpdate() {
            //判断添加还是修改
            if (this.$route.params && this.$route.params.id) {
                this.updateCourse()
            } else {
                this.addCourse()
            }
        }
    }
}
</script>
<style scoped>
    .tinymce-container {
        line-height: 29px;
    }
</style>